Power detector radio frequency multiplexer

ABSTRACT

A disclosed circuit arrangement may include a power detector. A multiplexer circuit may be coupled to the power detector. The multiplexer circuit may include at least two switching sections, one of the switching sections to pass a radio frequency (RF) signal generated based on a first modulation scheme to the power detector and another of the switching sections to pass an RF signal generated based on a second modulation scheme to the power detector.

BACKGROUND

Wireless systems generally need to control radio frequency (RF) outputto ensure transmitted signals are within acceptable regulated limits.For battery powered wireless systems and devices, controlling RF outputmay increase battery life. There are many other reasons to monitor andcontrol RF output from wireless devices.

Power detectors are used in wireless systems to monitor the power of anRF signal that is output to an antenna. Generally, a power detectorproduces a direct current (DC) signal that is proportional to the powerof the RF signal being sampled. A wireless system may use the DC signalas a measure of the power of the RF signal being transmitted, andthereby make adjustments in order to maintain the output power withinsystem specifications.

Multi-band wireless systems are capable of receiving and transmittingover a wide frequency bandwidth, which may cover a plurality of wirelessstandards. For example, a multi-band wireless system may be configuredto receive and transmit signals associated with the Global Standard forMobile (GSM) digital system and the Advanced Mobile Phone System (AMPS)analog system. Such a multi-band wireless system generally employsmultiple power detectors to monitor the power of the various RF signalsoutput from the wireless system. The use of multiple power detectors ina multi-band wireless system adds to the overall number of componentsused to realize the system, which affects at least manufacturing costs,system size and may increase the complexity of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items.

FIG. 1 is a block diagram illustrating components of a multi-bandwireless system incorporating at least one exemplary implementation of apower detector multiplexer.

FIG. 2 illustrates a schematic circuit diagram including a powerdetector multiplexer coupled to a number of components associated with awireless system. The illustrated power detector multiplexer is capableof receiving radio frequency (RF) signals associated with a plurality ofwireless standards, and passing such received signals to a single powerdetector.

FIG. 3 illustrates a schematic circuit diagram including a powerdetector multiplexer coupled to a number of components associated with awireless system. The illustrated power detector multiplexer is capableof receiving radio frequency (RF) signals, including differential RFsignals, associated with a plurality of wireless standards, and passingsuch received signals to a single power detector.

DETAILED DESCRIPTION

Overview

At least one implementation described herein substantially eliminatesthe use of multiple power detectors in a wireless system. Using fewerpower detectors, or a single power detector, may reduce the size ofwireless systems. Moreover, the use of fewer power detectors may reducethe costs of manufacturing wireless systems.

In one exemplary implementation, a power detector multiplexer is used ina wireless system that supports multiple wireless standards. Suchstandards may include, for example, the Global Standard for Mobile(GSM), Advanced Mobile Phone System (AMPS), code division multipleaccess (CDMA), and cdma2000. The power detector multiplexer may receivea plurality of radio frequency (RF) signals associated with diversewireless standards. The power detector multiplexer is capable ofselecting and routing each of one of the received plurality of RFsignals to a common power detector. The power detector multiplexer mayinclude direct current (DC) blocking capacitors and switches that selectand route the RF signals received thereby.

In another exemplary implementation, a power detector multiplexer isused in a wireless system that supports multiple wireless standards andgenerates differential RF signals. The wireless standards supported bythe wireless system may include, for example, GSM, AMPS, CDMA, andcdma2000. The power detector multiplexer may receive a plurality ofradio (RF) signals associated with diverse wireless standards. Theplurality of RF signals may include differential RF signals. Associateddifferential signals, such as those generated by a quadrature generator,generally have the same frequency, but one differential signal may bedelayed one quarter cycle or period with respect to another differentialsignal in a differential signal pair. The power detector multiplexer iscapable of selecting and routing each one of the received plurality ofRF signals, or routing each differential signal pair, to a common poweramplifier. The power detector multiplexer may include DC blockingcapacitors and switches that select and route the RF signals receivedthereby.

Exemplary Arrangements

FIG. 1 is a block diagram illustrating components of a multi-bandwireless system 100 incorporating at least one exemplary implementationof a power detector multiplexer 102. As will be discussed in furtherdetail herein, the power detector multiplexer 102 is capable ofreceiving and processing RF signals sampled from a plurality of RFsignal sources.

The multi-band wireless system 100 includes a modulator 104. Themodulator 104 is capable of receiving voice or other data for modulationto a transmission frequency. If a signal received by the modulator 104is for modulation at a first frequency band (e.g., for GSM), then thesignal may be processed by a power amplifier I 106. Alternatively, if asignal received by the modulator 104 is for modulation at a secondfrequency band (e.g., for AMPS), then the signal may be processed by apower amplifier II 108. If the multi-band wireless system 100 is capableof handling more than two wireless standard modulation techniques, thenadditional power amplifiers N 110 may be implemented.

After a signal is amplified by the power amplifier I 106, the amplifiedsignal is passed to a coupler 112. The coupler 112 passes a majority ofthe amplified signal to a transmit and receive switch 114. The transmitand receive switch 114 passes the amplified signal to a duplexer 116that passes the signal to a multi-band antenna 118 for wirelesstransmission to a receiving device (not shown). Similarly, after asignal is amplified by the power amplifier II 108, the amplified signalis passed to a coupler 120. The coupler 120 passes a majority of theamplified signal to a transmit and receive switch 122. The transmit andreceive switch 122 passes the amplified signal to the duplexer 116 thatpasses the signal to the multi-band antenna 118 for wirelesstransmission to a receiving device. If additional power amplifiers N 110are implemented, then couplers N 124 and transmit and receive switches N126 may be used in the multi-band wireless system 100.

Each coupler 112, 120 and 124 is interfaced with the power detectormultiplexer 102. A portion of the signals passed through the couplers112, 120 and 124 may be received by the power detector multiplexer 102and processed thereby. An output of the power detector multiplexer 102may be coupled to a power detector 128. The power detector 128 iscapable of rectifying a received RF signal and converting the rectifiedRF signal to a DC signal that is proportional to the strength of an RFsignal output from the power amplifiers 106, 108, and 110. The DC signalproduced by the power detector 128 is input to a control microprocessor130, or other similar control device. The control microprocessor 130 maysignal a variable gain amplifier (VGA) or voltage variable attenuator(VVA), as the initial power sensing feedback stage within the modulator110, to adjust a transmission power in accordance with predeterminedtransmission power requirements.

FIG. 2 illustrates a schematic circuit diagram 200 including a powerdetector multiplexer 202 coupled to a number of components associatedwith a wireless system. The illustrated power detector multiplexer 202is capable of receiving RF signals associated with a plurality ofwireless standards, and passing such received signals to a single powerdetector 204. The power detector 204 may be interfaced with a controlprocessor 206. The control processor 206 may function in substantiallythe same manner as discussion in relation the control processor 130. Theschematic circuit diagram 200 including the power detector multiplexer202 may be used with a wireless system, such as the multi-band wirelesssystem 100 illustrated in FIG. 1.

The power detector multiplexer 202 illustrated in FIG. 2 includes twoswitching sections 208 and 210. The switching section 208 is enabled andcapable of passing an RF₁ signal when a switch 212 is in a closed state.An additional switch 214 is included in the switching section 208. Whenthe switch 212 is in the closed state, the additional switch 214 is inan open state. Generally, the additional switch 214 is used to terminatesignals to ground when the switch 212 is in the open state. Tosummarize, when the switch 212 is in the closed state, the switch 214 istoggled to the open state, and when the switch 212 is in the open state,the switch 214 is toggled to the closed state. The RF₁ signal may be thetype generated based on a first wireless standard modulating scheme. Theswitching section 208 may also include capacitors 216 and 218. Thecapacitor 216 is used to block DC signals and the capacitor 218 may begenerally considered a parasitic capacitance.

The switching section 210 is enabled and capable of passing an RF₂signal when a switch 220 is in a closed state. An additional switch 222is included in the switching section 210. When the switch 220 is in theclosed state, the additional switch 222 is in an open state. Generally,the additional switch 222 is used to terminate signals to ground whenthe switch 220 is in the open state. To summarize, when the switch 220is in the closed state, the switch 222 is toggled to the open state, andwhen the switch 220 is in the open state, the switch 222 is toggled tothe closed state. The RF₂ signal may be the type generated based on asecond wireless standard modulating scheme. The switching section 210may also include capacitors 224 and 226. The capacitor 224 is used toblock DC signals and the capacitor 226 may be generally considered aparasitic capacitance.

The switching sections 208 and 210 may be controlled by the controlprocessor 206, or another alternative controlling mechanism.Operationally, the switching section 208 is enabled to pass an RF signalto the power detector 204 when the RF₁ signal is present at an input ofthe power detector multiplexer 202. This is made possible by togglingthe switch 212 to a closed state and toggling the switch 214 to an openstate. In conjunction with the toggling of switches 212 and 214, in thecase of passing the RF₁ signal through the multiplexer 202, the switch220 should be toggled to the open state and the switch 222 should betoggled to the closed state. The switching section 208 is generally notenabled to pass an RF signal if a signal is not present at an inputthereof.

The switching section 210 is enabled to pass an RF signal to the powerdetector 204 when the RF₂ signal is present at an input of the powerdetector multiplexer 202. Because the switching section 210 operates insubstantially the same manner as discussed in connection with theswitching section 208, a detailed discussion of the switches 220 and 222is not provided. The switching section 210 is generally not enabled topass an RF signal if a signal is not present at an input thereof.

The design of the power detector multiplexer 202, in particular theability to process and route at least two RF signals having diversemodulation properties (e.g., GSM and CDMA), substantially eliminates theneed to use multiple power detectors in a wireless system. This mayenable the manufacture of more compact wireless systems. Although thepower detector multiplexer 202 illustrated in FIG. 2 is shown having thecapacity to process two RF signals, additional switching sections may beimplemented to enable the processing of N RF signals.

In addition, although the power detector multiplexer 202 is shown asreceiving two RF signals, the power detector multiplexer 202 may alsoreceive on one input an RF signal and on the other input a referencesignal. This reference signal may be used to calibrate the powerdetector 204. In some implementations, the reference signal is asinusoidal signal in the GHz range. However, the reference signal mayalso be in the MHz range. One exemplary system that makes use of such areference to the signal is an ultra wideband (UWB) radio.

FIG. 3 illustrates a schematic circuit diagram 300 including a powerdetector multiplexer 202 coupled to a number of components associatedwith a wireless system. The illustrated power detector multiplexer 302is capable of receiving differential RF signals associated with aplurality of wireless standards, and passing such received signals to asingle power detector 304. The power detector 304 may be interfaced witha combiner 306 that is coupled to a control processor 308. The combiner306 is capable of combining differential RF signals output from thepower detector multiplexer 302. The control processor 308 may functionin substantially the same manner as discussed in relation the controlprocessor 130 and 206. The schematic circuit diagram 300 including thepower detector multiplexer 302 may be used with a wireless system, suchas the multi-band wireless system 100 illustrated in FIG. 1.

The power detector multiplexer 302 illustrated in FIG. 3 operates in asimilar manner to the power detector multiplexer 202, with the exceptionbeing that the power detector multiplexer 302 is capable of processingdifferential RF signals. Unlike single RF signals, differential RFsignals are generally comprised of two RF signals (in-phase andquadrature phase signals) that need to be summed or combined beforetransmission. The power detector multiplexer 302 makes it possible touse a single power detector in a wireless system that makes use ofdifferential RF signals.

The power detector multiplexer 302 has a first differential RF signalinput signal section 310 and a second differential RF signal inputsection 312. The first section 310 allows either an I (in-phase) signal(RF_(1n)) associated with a first differential signal pair or an Isignal (RF_(2n)) associated with a second differential signal pair topass to the power detector 304. The second section 312 allows either a Q(quadrature phase) signal (RF_(1p)) associated with the firstdifferential signal pair or a Q signal (RF_(2p)) associated with thesecond differential signal pair to pass to the power detector 304.Although differential I and Q carrier signals are discussed as beingprocessed by the power detector multiplexer 302, other combinable RFsignals may also be processed by the multiplexer 302.

The first differential RF signal input signal section 310 includes afirst switching section 314. The first switching section 314 is enabledand capable of passing an RF_(1n) signal when a switch 316 is in aclosed state. An additional switch 318 is included in the switchingsection 314. When the switch 316 is in the closed state, the additionalswitch 318 is in an open state. Generally, the additional switch 318 isused to terminate signals to ground when the switch 316 is in the openstate. To summarize, when the switch 316 is in the closed state, theswitch 318 is toggled to the open state, and when the switch 316 is inthe open state, the switch 318 is toggled to the closed state. TheRF_(1n) signal may be the type generated based on a first wirelessstandard modulating scheme that makes use of differentially modulatedsignals. The first switching section 314 may also include capacitors 320and 322. The capacitor 320 is used to block DC signals and the capacitor322 may be generally considered a parasitic capacitance.

The second differential RF signal input signal section 312 includes afirst switching section 324 that operates in conjunction with the firstswitching section 314. The first switching section 324 is enabled andcapable of passing an RF_(1p) signal when a switch 326 is in a closedstate. An additional switch 328 is included in the switching section324. When the switch 326 is in the closed state, the additional switch328 is in an open state. Generally, the additional switch 328 is used toterminate signals to ground when the switch 326 is in the open state. Tosummarize, when the switch 326 is in the closed state, the switch 328 istoggled to the open state, and when the switch 326 is in the open state,the switch 328 is toggled to the closed state. The RF_(1p) signal may bethe type generated based on a first wireless standard modulating schemethat makes use of differentially modulated signals. The first switchingsection 324 may also include capacitors 330 and 332. The capacitor 330is used to block DC signals and the capacitor 332 may be generallyconsidered a parasitic capacitance.

The switching sections 314 and 324 function cooperatively to passdifferentially paired signals, such as differential signals RF_(1n) andRF_(1p), to the power detector 304. In one implementation, the switchingsections 314 and 324 may be controlled by the control processor 206, oranother alternative controlling mechanism. After the differentialsignals RF_(1n) and RF_(1p) are processed by the power detector 304, thesignals are combined by the combiner 306 and output to the controlprocessor 308 for subsequent transmission via an antenna.

The first differential RF signal input signal section 310 includes asecond switching section 334. The second switching section 334 isenabled and capable of passing an RF2 _(n) signal when a switch 336 isin a closed state. An additional switch 338 is included in the switchingsection 334. When the switch 336 is in the closed state, the additionalswitch 338 is in an open state. Generally, the additional switch 338 isused to terminate signals to ground when the switch 336 is in the openstate. To summarize, when the switch 336 is in the closed state, theswitch 338 is toggled to the open state, and when the switch 336 is inthe open state, the switch 338 is toggled to the closed state. The RF2_(n) signal may be the type generated based on a second wirelessstandard modulating scheme that makes use of differentially modulatedsignals. The switching section 334 may also include capacitors 340 and342. The capacitor 340 is used to block DC signals and the capacitor 342may be generally considered a parasitic capacitance.

The second differential RF signal input signal section 312 includes asecond switching section 344 that operates in conjunction with thesecond switching section 334. The second switching section 344 isenabled and capable of passing an RF_(2p) signal when a switch 346 is ina closed state. An additional switch 348 is included in the switchingsection 344. When the switch 346 is in the closed state, the additionalswitch 348 is in an open state. Generally, the additional switch 348 isused to terminate signals to ground when the switch 346 is in the openstate. To summarize, when the switch 346 is in the closed state, theswitch 348 is toggled to the open state, and when the switch 346 is inthe open state, the switch 348 is toggled to the closed state. TheRF_(2p) signal may be the type generated based on a second wirelessstandard modulating scheme that makes use of differentially modulatedsignals. The switching section 344 may also include capacitors 350 and352. The capacitor 350 is used to block DC signals and the capacitor 352may be generally considered a parasitic capacitance.

The switching sections 334 and 344 function cooperatively to passdifferentially paired signals, such as differential signals RF2 _(n) andRF_(2p), to the power detector 304. In one implementation, the switchingsections 334 and 344 may be controlled by the control processor 308, oranother alternative controlling mechanism. After the differentialsignals RF_(1n) and RF_(1p) are processed by the power detector 304, thesignals are combined by the combiner 306 and output to the controlprocessor 308 for subsequent transmission via an antenna.

The design of the power detector multiplexer 302, in particular theability to process and route at least two differentially paired RFsignals having diverse modulation properties (e.g., GSM and CDMA),substantially eliminates the need to use multiple power detectors in awireless system. This may enable the manufacture of more compactwireless systems. Although the power detector multiplexer 302illustrated in FIG. 3 is shown having the capacity to process twodifferentially paired RF signals, additional switching sections may beimplemented to enable the processing of N differentially paired RFsignals.

The exemplary power detector multiplexers 202 and 302 may be employed bya computing device, such as a computer that includes wirelessfunctionality, a wireless phone, a wireless base station, a network canaccess device, (e.g., a broadband access device), a personal digitalassistant (PDA), and so on. Such computing devices may includeintegrated circuits (ICs) that have one or more of the power detectormultiplexers 202 and 302 integrated therein. As those skilled in the artappreciate, such ICs may include processors, memories, amplifiers,receivers, transceivers, and so forth.

The technology shown in FIGS. 1-3 is merely illustrative of a select fewcomponents that may be used to design the illustrated implementations.Those of ordinary skill in the art appreciate many other componentcombinations may be used to develop the devices illustrated in thefigures.

Conclusion

For the purposes of this disclosure and the claims that follow, theterms “coupled” and “connected” have been used to describe how variouselements interface. Such described interfacing of various elements maybe either direct or indirect. Although the subject matter has beendescribed in language specific to structural features and/ormethodological acts, it is to be understood that the subject matterdefined in the appended claims is not necessarily limited to thespecific features or acts described. Rather, the specific features andacts are disclosed as example forms of implementing the claims.

What is claimed is:
 1. A circuit arrangement, comprising: a powerdetector; and a multiplexer circuit coupled to the power detector, themultiplexer circuit including at least two switching sections, one ofthe switching sections to pass a radio frequency (RF) signal generatedbased on a first modulation scheme to the power detector and another ofthe switching sections to pass an RF signal generated based on a secondmodulation scheme to the power detector, wherein the power detector iscommon to the at least two switching sections.
 2. The circuit accordingto claim 1, wherein each of the at least two switching sections includesa switch that enables RF signals to pass to the power detector, theswitch of each of the at least two switching sections to pass RF signalsto the power detector when in a closed state.
 3. The circuit accordingto claim 2, wherein the switch of each of the at least two switchingsections prevents RF signals to pass to the power detector when in anopen state.
 4. The circuit according to claim 1, wherein each of the atleast two switching sections includes a switch that enables RF signalsto pass to ground, the switch of each of the at least two switchingsections to pass RF signals to ground when in a closed state.
 5. Thecircuit according to claim 4, wherein the switch of each of the at leasttwo switching sections prevents RF signals to pass to ground when in anopen state.
 6. The circuit according to claim 1, wherein each of the atleast two switching sections includes a switch that enables RF signalsto pass to the power detector and another switch that enables RF signalsto pass to ground, the switches of each of the at least two switchingsections toggled oppositely when the multiplexer circuit is activelyprocessing any RF signal.
 7. The circuit according to claim 1, whereineach of the at least two switching sections includes two switches inparallel, one of the switches coupled to ground and another of theswitches coupled to an input of the power detector.
 8. The circuitaccording to claim 7, wherein each of the at least two switchingsections includes a capacitor, each capacitor of the at least twoswitching sections coupled to the at least two switches of a respectiveone of the at least two switching sections.
 9. A circuit arrangement,comprising: a power detector; and a multiplexer circuit coupled to thepower detector, the multiplexer circuit including at least fourswitching sections, two of the switching sections to pass differentialradio frequency (RF) signals generated based on a first modulationscheme to the power detector and another two of the switching sectionsto pass differential RF signals generated based on a second modulationscheme to the power detector.
 10. The circuit according to claim 9,wherein each of the at least four switching sections includes a switchthat enables RF signals to pass to the power detector, the switch ofeach of the at least four switching sections to pass RF signals to thepower detector when in a closed state.
 11. The circuit according toclaim 10, wherein the switch of each of the at least four switchingsections prevents RF signals to pass to the power detector when in anopen state.
 12. The circuit according to claim 9, wherein each of the atleast four switching sections includes a switch that enables RF signalsto pass to ground, the switch of each of the at least four switchingsections to pass RF signals to ground when in a closed state.
 13. Thecircuit according to claim 12, wherein the switch of each of the atleast four switching sections prevents RF signals to pass to ground whenin an open state.
 14. The circuit according to claim 9, wherein each ofthe at least four switching sections includes two switches in parallel,one of the switches coupled to ground and another of the switchescoupled to an input of the power detector.
 15. A wireless system,comprising: an integrated circuit having a multiplexer circuit, themultiplexer circuit including at least two switching sections, one ofthe switching sections to pass a radio frequency (RF) signal generatedbased on a first modulation scheme and another of the switching sectionsto pass an RF signal generated based on a second modulation scheme,wherein the multiplexer circuit of the integrated circuit is coupled toa single power detector.
 16. A method, comprising: receiving at leasttwo radio frequency (RF) signals, one of the at least two received RFsignals generated based on a first modulation scheme and another of theat least two received RF signals generated based on a second modulationscheme; processing the at least two RF signals by way of a multiplexercircuit, the multiplexer circuit including at least two switchingsections, one of the switching sections to pass RF signals generatedbased on a first modulation scheme and another of the switching sectionsto pass RF signals generated based on a second modulation scheme; anddetecting signal attributes associated with each of the at least two RFsignals by way of a common power detector.
 17. The method according toclaim 16, wherein the received at least two RF signals includedifferential RF signals.
 18. The method according to claim 16, whereineach of the at least two switching sections of the multiplexer circuitincludes a switch that enables RF signals to pass to the common powerdetector, the switch of each of the at least two switching sections topass RF signals to the common power detector when in a closed state. 19.A circuit arrangement, comprising: a power detector; and a multiplexercircuit coupled to the power detector, the multiplexer circuit includingat least two switching sections, one of the switching sections to pass aradio frequency (RF) signal generated based on a first modulation schemeto the power detector and another of the switching sections to pass areference signal.
 20. The circuit arrangement according to claim 19,wherein the circuit arrangement is employed in an ultra wideband system.21. A circuit arrangement, comprising: a power detector; and amultiplexer circuit coupled to the power detector, the multiplexercircuit including at least two switching sections, one of the switchingsections to pass a signal generated based on a modulation scheme to thepower detector and another of the switching sections to pass a signal tocalibrate the power detector.
 22. The circuit according to claim 21,wherein each of the at least two switching sections includes a switchthat enables signals to pass to the power detector, the switch of eachof the at least two switching sections to pass signals to the powerdetector when in a closed state.
 23. The circuit according to claim 22,wherein the switch of each of the at least two switching sectionsprevents signals to pass to the power detector when in an open state.24. The circuit according to claim 21, wherein each of the at least twoswitching sections includes a switch that enables signals to pass toground, the switch of each of the at least two switching sections topass signals to ground when in a closed state.
 25. The circuit accordingto claim 23, wherein the switch of each of the at least two switchingsections prevents signals to pass to ground when in an open state. 26.The circuit according to claim 21, wherein each of the at least twoswitching sections includes a switch that enables signals to pass to thepower detector and another switch that enables signals to pass toground, the switches of each of the at least two switching sectionstoggled oppositely when the multiplexer circuit is actively processingany signal.
 27. The circuit according to claim 21, wherein each of theat least two switching sections including two switches in parallel, oneof the switches coupled to ground and another of the switches coupled toan input of the power detector.
 28. The circuit according to claim 27,wherein each of the at least two switching sections includes acapacitor, each capacitor of the at least two switching sections coupledto the at least two switches of a respective one of the at least twoswitching sections.
 29. A wireless system, comprising: an integratedcircuit having a multiplexer circuit, the multiplexer circuit includingat least two switching sections, one of the switching sections to pass asignal generated based on a modulation scheme and another of theswitching sections to pass a calibration signal, wherein the multiplexercircuit of the integrated circuit is coupled to a single power detector.30. The wireless system according to claim 29, wherein the multiplexercircuit of the integrated circuit is coupled to a single power detector.31. The wireless system according to claim 30, wherein the calibrationsignal is to calibrate the single power detector.